The present invention relates to a cellulose hard capsule prepared using the mixed solution of pectin and glycerin and its preparation method thereof.
Hard capsules are widely used in the pharmaceutical industry as well as in the health food supplement market. The main usage thereof is as dosage form for solid, semi-solid, liquid, pellet or herbal preparations. A primary objection of these dosage forms is to have a good disintegration after being administered in order to enable an effective dissolution of the active substances in the appropriate digestive organ. Consequently, this disintegration characteristic has to remain stable over time when finished products are stored prior to use.
The traditional material for forming the capsule is gelatin, because it has the correct and quite ideal properties. Nevertheless, gelatin has some disadvantages which make it necessary to have other capsule materials available. A major unfavorable aspect is the animal origin of gelatin. Other disadvantages are the inconveniences of relatively high water content (10xcx9c16%) and the loss of elasticity with decreasing water content. Furthermore gelatin capsules are sensitive to heat and humidity which affects the usability of the product.
As a gelatin substitute the use of water soluble capsule, the cellulose derivatives have been disclosed in some literatures. However, in the case of using cellulose derivatives as capsule material, the gelling agent has to be included in the capsule composition.
U.S. Pat. No. 5,431,917 disclosed a method for preparing cellulose hard capsule using the carrageenan as gelling agent and potassium ion as co-gelling agent. Further, WO 98/27151 disclosed a cellulose capsule using gellan gum as gelling agent. Even though pectin had been expected in this publication as a gelling agent equivalent to gellan gum or carrageenan, the pectin itself cannot be used as a gelling agent due to its low gelling property caused by the hydrolysis of pectin when it is applied to cellulose capsule.
Pectin is a hydrocolloidal compound used as thickening agent, jellifying agent or texturizer in food processing, especially, in jam, jelly or squeezed juice processing. If pectin is applied to hard capsule component, it makes hard capsule be stable compared to other gelling agent on condition that pectin overcomes the problem of hydrolysis property.
Pectin is a kind of polysaccharide forming a plant tissue as colloidal material, which consists of methylester of polygalacturonic acid bound to hemicellulose or xcex1-cellulose.
Pectin can be classified into three groups under the degree of methyl esterification of carboxyl group in a pectin molecule; i) high methoxyl pectin: more than 50% of degree of esterification and more than 7% of methoxyl content; ii) low methoxyl pectin: less than 50% of degree of esterification and less than 7% of methoxyl content; iii) low methoxyl amide pectin: amine radical is replaced by methyl radical in esterification.
All of pectins can be reacted with calcium. Through the reaction with calcium, high methoxyl pectin slightly increases its viscosity, whereas low methoxyl pectin forms flexible gel. However, according to the lapse of time for reaction or storage, the gel formation property suddenly declines due to the hydrolysis of pectin molecule.
Although pectin has above drawbacks, it may be used successfully in confectionery industry for gum, cookie, jelly etc. However, due to the hydrolysis of pectin molecule in the mixed solution, it can not be used for gelling agent to the preparation process of cellulose capsule, which comprises following steps of: i) dispersing mixed solution over 80xc2x0 C. and solubilizing it under 50xc2x0 C. at least for 24xcx9c36 hours; ii) stabilizing the solution at 53xcx9c55xc2x0 C. after adjusting the viscosity and removal of bubble; and iii) forming a capsule using molding pin. Therefore, the mixed solution for making hard capsule has to be continuously gelled more than 20 hours for making a film
If pectin is used as gelling agent for making cellulose capsule, we can not obtain a desirable product, because gelling property of pectin declines only after 12 hours gellation caused by hydrolysis of pectin molecule.
To solve above drawback of pectin, the present invention developed a process for preparing cellulose capsule using pectin mixed solution, which does not decline the gelling property over a lapse of more than 12 hours.
The object of the present invention is to provide a process for preparing cellulose capsule comprising the steps of: i) preparing a mixed solution of pectin and glycerin, ii) adding said mixed solution to solubilized cellulose aqueous solution, iii) adding a small amount of glacial acetic acid, calcium gluconate, sucrose fatty acid ester to said mixture, and iv) standing by adjusting viscosity and forming a capsule.
Another object of the present invention is to provide a cellulose capsule comprising i) 15xcx9c23 wt % of cellulose derivatives, ii) 0.3xcx9c1.1 wt % of low methoxyl amide pectin, and iii) 0.04xcx9c0.6 wt % of glycerin.
The other object of the present invention is to provide a cellulose capsule comprising i) 18xcx9c20 wt % of cellulose derivatives, ii) 0.6xcx9c0.8 wt % of low methoxyl amide pectin, iii) 0.1xcx9c0.3 wt % of glycerin, iv) 0.03xcx9c0.05 wt % of glacial acetic acid, v) 0.03xcx9c0.05 wt % of calcium gluconate, and vi) 0.2xcx9c0.5 wt % of sucrose fatty acid ester.